Evaluating the Carbon Footprint of Antibiotics Prescribed in Primary Care in Ireland

Introduction : The healthcare sector produces approximately 5% of global greenhouse gas emissions, with medicines responsible for 20–55% of this footprint. Antibiotics contribute significantly due to their high prescribing volumes and molecular complexity. In Ireland, the Health Service Executive (HSE) Green/Red Antibiotic Quality Improvement (QI) Initiative guides prescribers towards narrower-spectrum agents to reduce antimicrobial resistance (AMR), but its alignment with carbon footprint is unknown. Aim : To characterise the per-dose carbon footprint profile of antibiotics prescribed in Irish primary care from 2019 to 2023 and examine whether the HSE Green/Red Initiative aligns with lower carbon intensity. Method : Prescription data for 2019–2023 were obtained from the HSE-Primary Care Reimbursement Service (HSE-PCRS). Antibiotics with published Medicine Carbon Footprint (MCF) ratings were categorised by carbon intensity and compared by green/red listing. The trend in very high carbon prescribing was summarised by linear regression with a 95% confidence interval. Results : Of 23 antibiotics analysed, 21 had a high or very high carbon rating. Total prescriptions rose 18.3% between 2019 and 2023, while very high carbon prescriptions fell from 18.8% to 14.2% (-1.11 percentage points/year, 95% CI -2.07 to -0.14), driven by an 11.1% decline in macrolide prescribing. In 2023, 73.3% of red-listed prescriptions were very high carbon versus 0.8% of green-listed (risk difference 72.5 percentage points). Conclusion : The HSE Green/Red Initiative, designed to address AMR, carries a substantial synergistic environmental benefit: choosing a green-listed antibiotic is usually also the lower-carbon choice. Integrating MCF ratings into antimicrobial stewardship (AMS) frameworks would enable carbon-conscious prescribing without new guidance infrastructure.